When Should I Change My Air Conditioner's Air Filter at Home?

February 26, 2015

Need the short answer? Read our FAQ on "How often to change the air filter".

Every once in a while we’re asked what is the most important thing that Nashville area homeowner's can do to secure their air conditioning and heating system between their seasonal tune-ups? The answer is simple this; remember to change the heating and air conditioning air filter. Changing furnace and return air filters is critical to the effectiveness of your HVAC system, plus your home's air quality. Research suggests that indoor air pollution is one of the top five environmental health risks? You probably don’t consider it as you sit and watch TV, but this is the air you breathe day and night. Changing the air filters is not difficult for most Nashville homeowners, but there are often two obstacles to actually accomplishing this task:

Determining just how often to change your furnace or air conditioner filter.
Remembering to change air filters when needed.

When To Change Your Air Filters

Most filters have a timeline printed on the packaging. It may instruct "Lasts up to 3 months" or "Change filter every 90 days". Look around at the store and you should see that some are designed to only last one month, while other manufacturers (like Honeywell) have released media air cleaners with filters meant to be changed once every 6-12 months. The standard seems to be once every few months for most higher quality filters, but we have a rule of thumb that we suggest our readers to go by. If the filter is dirty, change it! A dirty air filter can add or cause damage to expensive parts, like your compressor, so it's best to change it out more often than to let it go. If you want to follow the manufacturer's recommended limit, we suggest marking the date on the filter when you swap it out, and setting a reminder for yourself in your phone or on a calendar. Keep in mind that your filter manufacturer sometimes has a different recommendation from your HVAC system manufacturer.

Determining how often to change your air filters can depend on several factors:

Type of filter your A/C system requires
The overall air quality of your Nashville area home
Pets – Cats, dogs, birds, etc.
Number of people in the home
General air pollution in the Nashville area or construction taking place nearby

For your standard 1"-3" air filters, the manufacturer specs basically tell you to change them every 1 or 2 months, which is in fact a great rule of thumb. However, general rules aren't always for everybody. If you have to endure light to moderate allergies, you might require an upgraded air filter or change them even more regularly than OEM specifications. On the other hand, if you're in a less populated area, own a infrequently occupied home (like a vacation home) or an area where there are fewer cars around, annual replacement of your air filter may be quite sufficient. Why should you factor in your pets? They have a tendency to shed, which can clog your air filter in no time, just like a vacuum. Obviously, the air filter is just doing its job by trapping pet hair and dander, but extremely dirty filters can cause diminished HVAC performance.

In summary:

Infrequently occupied home or single occupant homes without pets or allergies: Change 6-12 months
Typical suburban home without pets: Change every 90 days
Add a dog or cat: Change every 60 days
Several pets or have allergies: Change every 30-45 days

How To Remember To Change Your Air Conditioner's Air Filters

It's simple; sign up for the Service Experts Email Club. This is a convenient way to get money-saving discounts and other helpful information on your smartphone, tablet or desktop. Also, your email subscription preferences let’s you set a reminder to change your Nashville area home's air filter every 30, 60, 90, 120 or 365 days, or the date of your choosing.

How to replace your return air filter

Most people know how to replace the air filter in their unit, but some residences have an extra filter in the return ducts. Whether you have one or not is dependent on the HVAC manufacturer's recommendation. Your system is designed to handle a certain amount of pressure in your home sweet home, and the more filters you have the fiercer the blower motor works, which can reduce the life expectancy of your system if it isn't designed for it. Finding out whether you have a return filter and replacing it is a piece of cake:

Find your return air vents.
Some covers have screws and some have tabs. Unscrew or pull tabs to remove from the wall.
Check for a filter. If one is inside, pull it out and note the size.
Verify the filter type is the one recommended by the manufacturer.
If filter is dirty, replace with the manufacturer's recommended filter of the same size and type.

Crazy as it may seem, filters can greatly alter your home's airflow, which is why we recommend referring to the manufacturer. A more expensive HEPA filter that is designed to catch smaller particles will obstruct airflow more than a cheaper filter. With restricted airflow comes more pressure on your system, so you need to verify that your HVAC system was built to handle it. Otherwise, you might experience lowered heating and cooling efficiency in your home, and system parts may break down much faster than otherwise.

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